Gravity model toolbox: An automated and open-source ArcGIS tool to build and prioritize ecological corridors in urban landscapes

Abstract In an increasingly urbanized world, habitat fragmentation and lack of corridors among the fragmented habitats in urbanized ecosystems have compromised the survival of many species both at regional and global scale. Green corridors that connect isolated remnant habitat patches (e.g. parks) can increase connectivity and provide ecosystem services in cities. In the current study, we introduce an open-source ArcGIS toolset, the Gravity model toolbox, a programmed ArcGIS tool to map and prioritize the potential green corridors. The new toolset is based on the least-cost modelling and the improved gravity model, comprising of two script tools, the gravity model tool, and the network analysis tool. The gravity model tool can produce a spatially-explicit map of potential corridors for urban green space, as well as the prioritization of these corridors considered the opportunity cost. The network analysis tool is aimed at offering multiple scenarios of corridor networks based on the demands of users. To elucidate how the toolbox could be used by the urban planners and ecology researchers, a case study of the toolbox was conducted in the Tongzhou District, Beijing, China. This study presents a novel approach to assess urban connectivity and a systematic methodology for planning greening networks that connects landscape ecology with practical planning and designing considerations to maximize social and ecological functions of urban green space.